The present invention relates in general to regenerative liquid propellant guns and pertains, more particularly, to a modified conventional fixed bolt extending into a conventional combustion chamber of the regenerative liquid propellant gun. The modified fixed bolt of this invention provides for improved operation of the otherwise conventional regenerative liquid propellant gun.
With the conventional regenerative liquid propellant guns it is generally accepted that gun operation can produce unwanted high frequency pressure oscillations in a combustion chamber of the regenerative liquid propellant gun. It is further known or suspected that coherent propellant vortices, the probable cause of the oscillations, are generated by propellant flow over or across a trailing end of a conventional fixed bolt. Conventional wisdom postulated an unknown driving mechanism that was believed to create these vortices.
A drawback associated with coherent propellant vortices is the known consequence of a periodic heat release that can drive further unwanted pressure oscillations. The pressure oscillations are potentially destructive to the regenerative liquid propellant gun as the pressure oscillations may cause internal gun pressures in excess of those deemed operationally safe for a particular regenerative liquid propellant gun arrangement.
It is known that different regenerative liquid propellant guns have varying operating pressures. For example, as disclosed in U.S. Pat. No. 4,043,248 for a Liquid Propellant Gun (Recoilless Regenerative Piston), issued to Bulman et al., the gun may reach a peak pressure of 20,000 psi while a conventional projectile may not move significantly forward until an intermediate pressure of about 10,000 psi has been reached within the combustion chamber.